Vibrating pipe forming machine



Dec. 27, 1960 s. R. HUBBARD VIBRATING PIPE FORMING MACHINE 5 Sheets-Sheet 1 Filed Feb. 13, 1956 Q & mica/f lnv STEPHEN B. Hueaneq INVEN TOR.

.0. 5 n. a a N w? m i W e A W 6 OM Dec. 27, 1960 s. R. HUBBARD VIBRATING PIPE FORMING MACHINE Filed Feb. 13, 1956 3 Sheets-Sheet 2 JrEPHEA/ B. HUBBARD,

INVEN TOR.

UJZLWA .M

Dec. 27, 1960 s. R. HUBBARD 2,965,947

VIBRATING PIPE FORMING MACHINE Filed Feb. 13, 1956 3 Sheets-fiheet JJTEPHEN R. [IL/88,420, 'INVENTOR.

fi uencgi Beak/e1; Warre/ f 4912/?) ATTORNEYS- United States Patent VIBRATING PIPE FORMING MACHINE Stephen R. Hubbard, Compton, Calif., assignor to Cen- Vi-Ro Pipe Corporation, South Gate, Califl, a corporation of Delaware Filed Feb. 13, 1956, Ser. No. 564,957

9 Claims. (Cl. 25-30) The invention relates to concrete pipe-making ma chines and has particular reference to a centrifugal type vibrator mechanism for the purpose of improving the.

effectiveness of vibration.

The practice of casting concrete pipes by use of centrifugal molding machines has become widespread and the demand for concrete pipes of increased size, strength and quality has prevailed. To meet some of these requirements, vibrating the concrete while it is being deposited has already been resorted to. There are presently in existence a variety of types of vibrators worked into machinery of this character for the purpose of vibrating the pipe mold.

A great variety of types of vibration have some beneficial effect upon the deposit and distribution of moist concrete in a mold. Defects, however, have been extant and are exemplified by vibrating machinery wherein the vibration effect has not been sufficiently confined.

with the result that much of the energy needed for vibrating the mold is lost and wasted between the source of power and the mold. Vibrating devices have been sufficiently inefficient to demand sources of power far greater than commensurate with the amount of vibration actually made use of in the mold itself. Much of the lost vibration in prior devices has found its way into the frame and such stray vibrations in addition to being wasted cause an early deterioration in the frame and attached machinery.

'It is therefore among the objects of the invention to provide a new and improved centrifugal concrete pipe machine which depends upon vibration for the effective deposit of moist concrete and wherein a vibrating mechansim is provided which is highly effective in that the most desirable vibrations are applied directly to the mold and remaining vibrations are in effect cancelled out.

Another object of the invention is to provide a new and improved centrifugal concrete pipe machine wherein a vibrating mechanism is so constructed that it is capable of being operated by a source of power of far lesser amount than heretofore employed and wherein in spite of the decreased amount of power the vibrationalv effect upon the pipe mold is materially increased.

Still another object of the invention is to provide a new and improved vibrator for centrifugal concrete pipe machines wherein only useful vibrations are created in a vibrating head and wherein means is provided to apply these vibrations directly to the mold while at the same time substantially preventing the passing of vibrations to the frame of the machine.

Still another object of the invention is to provide a new and improved vibrator mechanism for a centrifugal pipe machine which is compact in size and dimension, which can be mounted singly or in multiple units immediately adjacent the rotating mold, and which is so designed and constructed as to permit effective operation of the vibrating mechanisms by motors operating at a high rate of revolutions per minute directly connected to the vibrating mechanism and productive thereby of a vibration effect of considerably greater force than heretofore employed which impinge directly on the pipe mold at the most advantageous location.

With these and other objects in view, the invention consists in the construction, arrangement and combination of the various parts of the device whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

In the drawings:

Figure 1 shows an end elevational view of a portion of a centrifugal concrete pipe machine showing the vibrating mechanism installed thereon.

Figure 2 is a plan view of the vibrating mechanism.

Figure 3 is a longitudinal sectional view of the vibrating mechanism taken on the line 3-3 of Figure 2.

Figure 4 is a cross-sectional view of the vibrating mechanism taken on the line 4-4 of Figure 3.

Figure 5 is a cross-sectional view taken on the line 5-5 of Figure 3..

Figure 6 is a horizontal sectional View taken on the line 66 of Figure 5.

In the embodiment of the invention chosen for the purpose of illustration the principal well-known portions of the device are shown in fragmentary form but in their operative relationship inasmuch as the over-all structural arrangement of such centrifugal concrete pipe machines is well known in the art. The machine is exemplified in the drawings by a frame 10 adapted to be carried by a suitable support 11. Mounted uponthe frame in the customary manner is a rotatable mold 12. Following a practice already established in the art, rotatable resilient supports in the form of cushioned wheels 13 are provided and mounted in such position relative to the mold that the mold is adapted to rest directly upon the cushioned wheels 13. The cushioned wheels may be idler wheels arranged in pairs at spaced locations along the mold except for one pair which may serve as drive wheels. The axes of the cushioned wheels in the chosen example are substantially parallel to. the axis of the mold 12.

The vibrator for the molding machine consists generally of a vibrating head 14, a mounting for securing the vibrating head upon the frame, a motor 16 for exciting the vibrating head and an adjusting device. 17 for elevating the vibrating head into engagement with the mold when desired and lowering it therefrom when the operation is complete.

By reason of the construction of the mechanism in the vibrating head, the electric motor 16 mounted upon the support 11 can be one having a high rate ofrotation. Effective performance has been achieved by usetof a motor rotating at a rate of 3.500 r.p.m. A flexible shaft 19 is connected with the aid of a suitable fitting or coupling 20 to a drive shaft 21 of the motor.

The mounting 15 includes spaced parallel plates 22 and 23, these being secured in proper position by ties 124. At one end of each plate is a bracket 25 adapted to have a clamp flange 26 attached thereto for securing a suitable bushing 27 in place. As a matter of compactness and convenience the bracket and clamp flange may be so mounted as to secure thebushing 27 around an extension 28 of the same shaft or axle whichv is employed to mount the adjacent cushioned wheel 13. Mounted by means of the structure described the plates are adapted to pivot about the extension 28' as a center of rotation within an arc sufllcientfor the needs of the machine.

To mount the vibrating head 14 upon-the mounting 15 the vibrating head is provided with an arm 29 which extends to a position between the plates 22 and 23.

On opposite sides of the arm 29 remote from the vibrating head are sleeves 30 and 31. The sleeves are shown in the embodiment selected as being mounted respectively on flanges 32 and 33 secured to the arm by means of bolts 34. On the plates 22 and 23 are respectively short lengths of tube 35 and 36. In a similar fashion flanges 37 and 38 for the respective tubes 35 and 36 are secured by bolts 39 to the adjacent plate. A resilient torque bushing 40 in the form of a ring is interposed between the sleeve 30 and the tube 35. A similar bushing 41 is contained between the sleeve 31 and tube 36. In each instance the bushing is cemented or otherwise fastened to the surrounding metallic elements so that as the sleeve rotates relative to the tube under the influence of vibration, the vibration is absorbed by the bushings and pre vented from passing from one metal element to the other.

The vibration head 14 more properly comprises a casing 45 which houses a chamber 46. A bearing housing 47 secured to the casing 45 by means of cap screws 45 serves also as a closure for the chamber 46. Rotatably mounted in the chamber 46 are respectively an eccentric drive shaft 48 and an eccentric countershaft 49. Suitable bearings 50 of conventional construction mount the shafts in the bearing housing at one end and in a side wall 51 of the casing 45 at the other end. On the eccentric drive shaft 48 is a single eccentric weight 52, the shape of which is more readily discerned in Figure 5. For imparting rotation to the eccentric drive shaft, the flexible shaft has a cable 53 thereof keyed non-rotatably to the eccentric drive shaft by means of a key 54. A flexible casing 55 for the flexible shaft is secured by a fitting 56 to a flexible shaft coupling anchor 57. The coupling anchor is in turn fastened to the side wall 51 by suitable screws 58.

To transmit motion from the eccentric drive shaft 48 to the eccentric countershaft 49, the spur gear 60 is keyed to the eccentric drive shaft 48 by means of a key 61 in a position where it meshes with a similar spur gear 62 keyed to the eccentric countershaft 49 by means of a key 63. The spur gears are equal in diameter so that the gear ratio is one to one and the eccentric shafts rotate at precisely the same rate.

On the eccentric countershaft two eccentric weights 64 and 65 are provided. These weights are spaced apart a distance sufficient to permit the weight 52 to pass between them. Moreover, the weights 64 and 65 are equal and have a combined weight equal to the weight 52 so that there is a perfect balance between the eccentric drive shaft and the eccentric countershaft.

It is important to note that the flexible shaft 19 follows a short direct route from the motor 16 to the vibrating head 14. To accomplish this an opening 70 is made through the extension 28 and a sleeve 71 inserted therein through which the flexible shaft 19 can pass. Similarly the bushing 27 is provided with an opening 72 on each side in alignment with the opening 70.

The flexible shaft 19 extends between the plates 22 and 23 and to accommodate mounting the shaft in proper position of alignment with the eccentric drive shaft the sleeve 30 is provided with a recess 75 slightly larger than the largest diameter of the flexible shaft.

illustrated in Figure 1 the vibrating head is shown in lnoperative position removed from contact with the mold 12. To shift the vibrating head upwardly so that a hammer 76 is elevated into contact with the bottom of the mold, the adjusting device 17 is operated. The adjusting device in the example shown comprises a hydraulic cylinder 77 pivotally attached at its lower end to a bracket 78 in turn carried by a hollow shaft 79. Shaft mountings 80 are employed to secure the hollow shaft to the support 11. A piston rod 81 forming part of the hydraulic cylinder extends upwardlly and is pivotally secured by a pin 82 to lugs 83 on the respective plates 22 and 23.

Hydraulic lines for operating the hydraulic cylinder are conventional and not shown.

In operation when a mold is to be vibrated during the depositing of moist concrete therein, the mold is first placed upon the frame, attached in the usual fashion and caused to be supported by the cushioned wheels 13. After rotation of the mold has begun and moist concrete is ready for depositing, the hammer 76 is lifted into engagement with the exterior of the mold at its lowermost point by operation of the adjusting device 17 evidenced by the hydraulic cylinder. When the fluid is passed to the cylinder, the piston 81 elevates the plates 22 and 23 and these in turn acting through the arm 29 raise the hammer 76. After the hammer has been adjusted to a position in contact with the mold 12, the motor 16 can be started. Thereafter with the motor rotating at a rapid rate of speed, the cable 53 rotates the eccentric drive shaft 48 and eccentric countershaft 49 rapidly at the same rate of speed. As the eccentric weights 52 on the eccentric drive shaft and 64 and 65 on the eccentric countershaft rotate, they rotate in opposite directions with the plates counterbalancing each other in a horizontal direction but augmenting each other in a vertical direction. Operating in this fashion, all of the vibration energy is directed up and down and none is directed laterally. Because of this lack of existence of stray vibrations, an extremely high frequency can be employed in a desired up and down direction sufficient to greatly increase the effectiveness of vibration on moist concrete deposited in the mold. Depending upon the length of the mold, one, two or more vibrating devices may be employed at suitable spaced distances along the length of the mold. Only one such device has been described. Others regardless of the number used are identical. Where more than one is used, each in turn is connected to the same source of hydraulic power so that all hammers would be elevated into operation simultaneously and subjected to the same hydraulic pressure to hold them in place.

The amplitude of the vibration may be kept relatively low and applied with considerable force. Vibrations of this type can be readily adjusted to perform most effectively depending upon the character of the moist concrete, the diameter and mass of the mold and other factors which may need to be taken into consideration in producing a product having the most desirable characteristics.

Despite the very high frequency of the vibrations which would ordinarily have a rather destructive effect should they stray into the framework of the machine, the vibrations are prevented from producing such a harmful effect because of being virtually all absorbed by the torque bushing. Moreover, the action of the torque bushing is rendered especially effective because of the fact that the vibrations are confined to motion in a single direction.

There has accordingly been described herein a particularly rugged, compact, and effective vibrating device for molds which, because of its ability to limit vibrations to a single direction, makes possible employment and control of vibrations having the most desirable frequency and amplitude applied to the mold at the most elfective locality. Further still, by controlling the vibrations as indicated by the structure described, many units can be applied to a single mold without a corresponding increase or change in the mounting or framework which might otherwise be necessary in more conventional structures to prevent an unwanted transmission and absorption of stray vibrations by the framework of the machine as a whole.

While I have herein shown and described my invention in which I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A mold vibrator for a pipe mold rotatably mounted on a supporting structure comprising a mounting, a pivotal connection attaching said mounting to the struc ture on a selected axis of rotation, a vibrating head located adjacent the mold, a bracket on the head and a vibration damping torque bushing assembly having parts respectively on the bracket and on the mounting, said torque bushing assembly having an axis parallel to the axis of rotation of the mounting and connecting said head with said mounting, a pair of interconnected counter-rotating balanced eccentric weights in said head mounted on eccentric shafts, said shafts being at right angles to the axis of the torque bushing and the axis of the mounting, a motor on the structure and a flexible drive shaft operatively connected respectively to the motor and to at least one of said eccentric shafts and adapted to vibrate said head during contact of the head with said mold whereby to vibrate said mold in a diametric direction during deposit of pipe material therein.

2. A mold vibrator for a pipe mold rotatably mounted on a supporting structure comprising a mounting, a pivotal connection attaching said mounting to the structure on a selected axis of rotation, a vibrating head located adjacent the mold, a bracket on the head and a vibration damping torque bushing assembly having parts respectively on the bracket and on the mounting, said mounting and the vibrating head having a path of movement toward and away from said pipe about said axis of rotation, said torque bushing assembly having an axis parallel to the axis of rotation of the mounting and connecting said head with said mounting, a pair of interconnected counter-rotating balanced eccentric weights in said head mounted on eccentric shafts, said shafts being at right angles to the axis of the torque bushing and the axis of the mounting, a motor on the structure and a flexible drive shaft operatively connected respectively to the motor and to at least one of said eccentric shafts in the vibrating head and adapted to vibrate said head during contact of the head with said mold whereby to vibrate said mold in a diametric direction during deposit of pipe material therein, and an adjustor assembly for the head comprising mutually movable parts respectively on the structure and on said mounting, said parts having an operatively extensible connection and acting in a direction coincident with the path of movement of the mounting and adapted to move said mounting and said head into and out of engagement with said mold.

3. A mold vibrator for a pipe mold rotatably mounted on a supporting structure comprising a mounting, a pivotal connection attaching said mounting to the structure on a selected axis of rotation, means forming a passage through said pivotal connection, a vibrating head located adjacent the mold, a bracket on the head, and a vibration damping torque bushing assembly having parts respectively on the bracket and on the mounting, said torque bushing assembly having an axis parallel to the axis of rotation of the mounting and connecting said head with said mounting, means forming a passage through said torque bushing assembly, a pair of interconnected counter-rotating balanced eccentric weights in said head mounted on eccentric shafts, said shafts being at right angles to the axis of the torque bushing and the axis of the mounting, a motor on the structure and a flexible drive shaft from the motor to at least one of said eccentric shafts extending through said passages adapted to vibrate said head during contact of the head with said mold whereby to vibrate said mold in a diametric direction during deposit of pipe material therein, and inhibit transmission of vibrations generated in the head to the mounting and the structure.

4. A mold vibrator for a pipe mold rotatably mounted on a supporting structure, said vibrator comprising a mounting, a rotatable connection pivotally attaching the mounting to the structure on a selected axis of rotation,

said mounting being movable about said axis in a path of movement about said axis to positions toward and away from said mold, a vibrating head located adjacent the mold, said vibrating head having a rotatable eccentric weight means therein and a bracket on the head and means isolating the vibrating head and bracket from vibration transmitting engagement with the structure, said means including a vibration damper comprising a plurality of spaced retaining elements and a vibration damping pad fixed therebetween, one of said retaining elements being connected to said bracket at a location removed from said head and another of said retaining elements being connected to said mounting, a motor on the supporting structure and a flexible drive shaft connected respectively to the motor and to the rotatable eccentric weight means in said vibrating head for generating vibrations therein, an adjustor assembly for the head comprising mutually moving parts respectively on the structure and on said mounting, said parts having an operatively extensible connection, said adjustor assembly being adapted to move said mounting and said head in a direction coincident with said path of movement into and out of engagement with said mold, and an eccentric weighted vibrating member mounted in said head and adapted to vibrate said head during contact of said head with said mold.

5. A mold vibrator for a rotating pipe mold mounted on a supporting structure comprising a mounting, a pivotal connection attaching said mounting to the structure on an axis parallel to the axis of the mold, a vibrating head located below the mold, a bracket on the head and a vibration inhibiting torque bushing assembly having parts thereof respectively on the bracket and on the mounting, said torque bushing assembly having an axis parallel to the axis of the mold, an elevator on the structure connected to said mounting and connected through said torque bushing to the head thereon and adapted to raise and lower said head into and out of engagement with said mold, a pair of interconnected counter-rotating eccentric weights in said head mounted on eccentric shafts, said shafts having parallel axes at substantially right angles to the axis of the torque bushing, a motor on the structure and a flexible drive shaft from the motor extending through said mounting to one of said eccentric shafts and adapted thereby to vibrate said head during contact of the head with said mold whereby to vibrate said mold in a diametric direction during the deposit of pipe molding material therein.

6. A mold vibrator for a centrifugal concrete pipe machine comprising a frame, a rotating pipe mold mounted on the frame on a horizontal axis and a set of rotating cushioned supports mounted on shafts on the frame, said mold vibrator comprising an extension on one of said shafts, a mounting including spaced parallel plates pivotally secured at one end to said extension, inwardly projecting axially aligned tubes on the other end of said plates and an annular torque bushing of vibration-absorbing material around each tube, a vibration head comprising a casing having a weight chamber therein and mounted adjacent the mold at the lowermost portion, a pair of oppositely rotating eccentric elements of equal weight in said chamber mounted on shafts with axes perpendicular to the axis of the torque bushing, one of said eccentric elements comprising a flat eccentric extending radially from the respective shaft, the other of said weights comprising equal halves located one on each side of said first identified weight and adapted to overlie each other during a portion of the rotation, an arm having one end secured to the casing and having the other end receptive of opposite ends of said tubes, sleeves on opposite sides of the other end of said arm encasing the respective torque bushing, and a drive shaft connected to one of said shafts.

7. A mold vibrator for a centrifugal concrete pipe machine comprising a frame, a rotating pipe mold mounted on the frame, and a set of cushion supports for the mold mounted on the frame, said mold vibrator comprising a mounting including spaced parallel plates, a cylindrical projection on the frame, semi-cylindrical clamp means on said plates pivotally securing said mounting to said projection, a vibrating head having an arm located between said plates, a vibration damping torque bushing assembly comprising sleeve elements on the arm and tube elements on said plates and vibration damping bushings therebetween, eccentric shafts in said head having an interconnected drive and having oppositely rotating eccentric weights thereon, and a flexible drive shaft means on the frame connected to one of said shafts, means forming a passage through said clamp means and projection, and means forming a passage through said torque bushing assembly, said shaft means extending through said passages into operating engagement with said one of said shafts.

8. A mold vibrator for a centrifugal pipe mold rotatably mounted on a frame on a horizontal axis comprising a mounting including a pair of spaced parallel plates,

a cylindrical projection on the frame in position parallel to the mold, semi-cylindrical clamp means on said plates pivotally securing said mounting to said projection, spacers between said plates, a vibrating head having an arm with one end thereof attached to the head and the other end thereof located between said plates, a torque bushing assembly comprising a sleeve element on each side of said other end of the arm, a tube element on the side of each facing said other end and a vibration damping bushing element between each tube element and sleeve element, eccentric shafts in said head having oppositely rotating eccentric weights thereon, gears interconnecting said shafts, and a flexible drive shaft means for one of said shafts, means forming a passage through said clamp means and projection, means forming a passage through said torque bushing substantially in alignment with said one shaft, said shaft means extending through said passages and between said plates into opcrating engagement with said one eccentric shaft, and a position adjusting means between and connected respectively to the frame and the mounting and adapted to move the mounting and the head with the drive shaft means attached thereto to and from operating position.

9. A mold vibrator for a pipe mold rotatably mounted on a supporting structure, said mold vibrator comprising a mounting, a movable connection between an inner end of said mounting and said supporting structure movably securing said mounting to the structure, and an outer end of said mounting extending outwardly from the structure, an extensible adjustor in a position transverse to the direction of movement of the mounting having an anchored end secured to the structure and a movable end secured to the mounting, a vibration producing head in a position adjacent the pipe mold, an arm having one end attached a vibration damping assembly comprising to said vibration producing head, complementary pivotal elements respectively on the arm and the mounting, and a member of vibration inhibiting material secured between said elements forming the sole connection between the arm and-the structure, having a limited range of rotative movement whereby to enable adjustment of said head by said adjustor to and removed from a position against said mold, means forming passages respectively through said vibration damping assembly and through the movable connection between the mounting and the supporting structure, vibration producing elements in said head, a source of rotating power at a lo cation remote from said head, and a flexible drive shaft between said source and said vibration producing elements and extending through said passages whereby to inhibit transmission of vibrations generated in the vibration producing head to said source of rotating power.

References Cited in the file of this patent UNITED STATES PATENTS 1,675,560 Iubien July 3, 1928 2,446,818 Flam Aug. 10, 1948 2,555,688 Flam June 5, 1951 2,610,040 Emmons Sept. 9, 1952 2,703,916 Butler Mar. 15, 1955 2,722,044 Chanlund et al. Nov. 1, 1955 2,724,582 Huff Nov. 22, 1955 2,822,598 Chanlund et a1. Feb. 11, 1958 FOREIGN PATENTS 730,592 Great Britain May 25, 1955 

